As the related art for the technical field, JP 2009-295362 A (PTL 1) and JP 2002-203614 A (PTL 2) are disclosed. PTL 1 describes a box-type electronic module including a circuit board, a connector, a metal base, and a sealing cover, which are integrally formed. The circuit board includes an electronic component mounted thereon. The connector electrically couples the circuit board and an exterior. The metal base includes the circuit board mounted thereon and is bonded to the connector through an adhesive. The sealing cover covers the circuit board and the metal base. The connector includes a required number of metal terminals and a resin housing. The housing includes a socket portion into which a plug of an external harness is inserted and which is substantially parallel to the circuit board, and a terminal holding wall portion holding a metal terminal (refer to claim 1). PTL 2 describes a configuration in which a connector housing is attached to one terminal portion of an FPC harness, and another terminal portion of the FPC harness is coupled on circuit wiring of a mounting board 3 through a conductive adhesive. The connector housing constitutes a part of a connector that electrically couples the circuit wiring formed on the mounting board of an ECU and other circuit wiring. With this configuration, since the connector housing is coupled to the ECU through the FPC harness, the area of a connector housing mounting part on the mounting board of the ECU can be reduced. In addition, since the connector housing is attached to the outside of an ECU body, a height of the mounting board can be lowered and then a height of the entire ECU including a height of the body can be lowered. Therefore, downsizing of the ECU can be achieved.